It is well known in motor vehicles to provide an air bag module mounted to a vehicle. For example, a typical driver's side air bag module includes a generally circular inflator positioned partially within a bag opening of an air bag for discharging inflator gas to inflate the air bag upon sensing certain predetermined vehicle conditions. The undeployed air bag is folded atop the inflator and a module cover overlies the air bag, inflator and other module components. The cover commonly has tear lines or weakened portions that allow the cover to open during air bag inflation.
Typically, the inflator includes a main body portion which discharges gas and an outwardly extending inflator mounting flange. The module also includes an air bag retainer located within the bag opening of the air bag and including a central gas opening for receiving the inflator therethrough. It is also typical to connect the air bag retainer to the air bag by a first fastening mechanism, to connect the air bag retainer to the base plate by a second fastening mechanism, and to connect the inflator to the base plate by a third fastening mechanism. The air bag retainer, air bag, inflator, and cover are each connected to the base plate to form the air bag module. Typically, the first, second, and third fastening mechanisms are each composed of one or more parts.
In addition, the module typically includes a plurality of axially elongated mounting members mounted to the base plate to connect the module to a hub portion of a steering wheel. Since the module perimeter is typically wider than a perimeter of the steering column of a steering wheel assembly, the mounting members on the base plate are located outboard of the perimeter of the steering column such that access holes can be provided in the hub portion directly beneath the mounting members for rear release of the mounting members for disconnection of the module from the steering wheel.
Reduction in inflator size has enabled modules which have an outer perimeter smaller than an outer perimeter of the steering column. Thus, there is no longer plentiful room around the air bag opening to attach the multiplicity of fasteners that are required to independently connect all of the module components to each other. If mounting members are provided on the module, they will be located inboard of the outer perimeter of the steering column such that the mounting members are no longer accessible by access holes in the hub portion for rear release. In addition, the prior art multiplicity of fastening mechanisms required to retain the module components to each other along with the mounting members required to mount the module to the steering wheel greatly increases assembly time.